This application is copending with my other applications entitled "Drive Wheel Assembly" and "Idler Wheel Assembly."
The present invention relates generally to a drive system for a track type vehicle, and more specifically to a drive system which includes an endless flexible track, idler wheel assemblies, and a drive wheel assembly providing frictional engagement with the track as a primary source for driving the track under normal conditions and a sprocket type engagement for preventing slippage and driving the track under exceptional conditions.
Skid steer vehicles for use in construction and farming have been known for quite some time now and were made popular by the Melroe brothers of Gwinner, North Dakota. Vehicles of this type can be used with various types of equipment such as buckets, grapple forks, backhoes, and posthole augers. Typically, up until this time, skid steer type vehicles have had wheels and tires on each side of the vehicle which are driven independently of each other. Even though track type vehicles have been known for some time, none of the track related technology has been used and moreover none of the known track type vehicles have a drive system as taught by the instant invention. One prior art system, depicted in U.S. Pat. No. 3,120,409, shows an endless belt 10 with V-belt type construction used in conjunction with a pulley 40 having integrally formed sprockets and V-grooves. The V-grooves of pulley 40 provide the primary driving forces and the sprocket teeth, with their engagement in openings in the belt, providing the secondary, or backup, driving connection. Another endless traction assembly, depicted in U.S. Pat. No. 3,870,379, shows a flexible endless belt 14 driven by a drive sprocket 20 having teeth engaging in openings in the belt with a guide wheel 36 disposed adjacent to the drive sprocket to prevent the flexible belt from engaging the sprocket teeth all the way down to the root. Another track assembly, for a crawler type vehicle, depicted in U.S. Pat. No. 4,241,956, shows a drive wheel assembly having a sprocket 22 and cylindrical surfaces 88 on each of the cylinders 84 and 86, the surface being defined by an elastomeric sleeve 90. Yet another drive system, depicted in U.S. Pat. No. 4,453,611, shows a drive wheel assembly 31 which includes a drive sprocket 48 located between rims 46 and 47. Another drive system, depicted in U.S. Pat. No. 3,738,714, shows a pair of drive sprocket wheels 90 used in conjunction with bearing wheels 92. Finally, there is a drive sprocket wheel, depicted in U.S. Pat. No. 3,597,018, which includes an outer ring of one material for engaging the endless belt and an inner ring of natural or synthetic elastomeric resin for helping to absorb shocks that the endless belt may encounter. Clearly, none of these prior art systems anticipate the drive system as taught by the instant invention.